Can Too Many Ultrasounds and 3D/4D Ultrasounds Harm Your Baby?

For many parents-to-be, the ultrasound is a chance to see their baby for the first time. Ultrasound technology has been used in obstetrics for the last 50 years and proponents swear by them and assert that they are completely safe for both mother and baby.

As I hope many of us have learned by now, it is always good to take a step back and re-evaluate just what we’re doing to our bodies and our babies. Just because every mother before us did it, doesn’t mean that we should just go along with it and not question what the ultrasound does.

Just because something is non-invasive, doesn’t automatically make it safe.

Let’s take that step back now and look at the science and technology.

Ultrasound Basics

The ultrasound works by sending high frequency sound waves through the uterus which bounce off the baby. The computer translates the echoes produced by the “bouncing” into an image.

The purpose of an ultrasound is to tell you and your doctor/midwife how your baby is doing. It is an instrumental tool in confirming due dates, evaluating for birth defects, and overall fetal health.

But ultrasounds are only supposed to be done when medically indicated. Many healthy pregnancies should not require an ultrasound. (3)

Heat Caused by Ultrasounds Linked to Neurodevelopmental Problems

The concern about ultrasounds was first raised in 1982 when the World Health Organization published a report in which it explained that their research had shown “neurological, behavioral, developmental, immunological, haematological [blood] changes and reduced fetal weight” (2) as a result of ultrasound exposure. In 1984, the National Institutes of Health reported that the acoustic output of ultrasound waves in cases of birth defects was “usually high enough to cause considerable heat.” (2) In 2003, a report published in the International Journal of Hyperthermia confirmed that increased heat during pregnancy can cause “embryonic death, abortion, growth retardation and developmental defects” (2) and even a fever of just three degrees higher than normal body temperature for 24 hours can cause a “range of developmental defects.” (2)

In August of 2006, Pasko Rakic, chair of Yale School of Medicine’s Department of Neurobiology, announced the results of a study in which the brains of the offspring showed damage consistent with that found in the brains of people with autism after having been exposed to ultrasound radiation while in the womb. The same study also implicated ultrasound in neurodevelopmental problems in children, such as dyslexia, epilepsy, mental retardation, and schizophrenia, and showed that damage to brain cells increased with longer exposures. (2)

The issue is the sound waves and increase in temperature of fetal tissues.

We’ve probably all heard ultrasound stories where the baby moved or turned away from the transducer. “When fetuses move away from the stream of high-frequency sound waves, they may be feeling vibrations, heat or both. In 2001, research was published that “an ultrasound transducer aimed directly at a miniature hydrophone placed in a woman’s uterus recorded sound ‘as loud as a subway train coming into the station.’ ” (2) The FDA issued a warning in 2004 about the physical effects on tissue including jarring vibrations and an increase in temperature. (2)

Ultrasound technology uses non-ionizing radiation. Non-ionizing radiation (at about the same level as an ultrasound) is used to heat your food in the microwave and can give you a sunburn. (4) Many of us are already aware that pregnant women are told to avoid saunas and hot tubs during their pregnancy, and must be more diligent in keeping their body temperatures down on hot days. If the body gets too hot, systems start to shut down. So it is with an embryo or fetus – much more so.

It also interesting to note that ultrasound heats bone faster than muscle, soft tissue, or amniotic fluid. A baby’s skull, for example, can heat up up to 50 times faster in the third trimester because the bone is more calcified.

And, yet, despite the increasing evidence, the FDA approved an eight-fold increase in acoustic output for ultrasound machines. You can read more about the research in this article.

Unwavering Faith in our Doctors

One thing that concerned me when I was researching this article was a number of forums where moms were asking about ultrasounds. I was stunned to read several responses along the lines of “my doctor would never suggest anything that would be harmful,” or “The benefits outweigh the risks”. The case of the latter, if it is a high-risk pregnancy than strategic, medically required ultrasounds are probably warranted.

In the case of the former, I don’t want to sound as if I’m saying don’t trust your doctor or not do what your doctor says; but we do need to be careful that we do not just hand off our responsibility and right as patients and mothers to our doctors or midwives. You are well within your right to say, “No.” An ultrasound is not compulsory. While it is probably a good idea from a medical standpoint to have at least one ultrasound during your pregnancy — and there are conditions where multiple ultrasounds are indicated in high-risk pregnancies — unless there is a medical reason for the ultrasound, it is not required. (3)

Let’s not just hand our lives and our babies’ lives over on a silver platter. Let’s take the same care with this decision as we do about eating right and quitting smoking and avoiding alcohol and avoiding overexposure to the sun during pregnancy.